Slack removal apparatus

ABSTRACT

An improvement in apparatus for maintaining a predetermined stress in a running-in string disposed in a well bore underlying a body of water and which is supported by a rig including a derrick and a floor or deck mounted on a barge or the like floating in the body of water. The rig has a block and tackle including a crown block and a traveling block with line therebetween. At least one line extends from the crown block to a support at a lower portion of the rig. Means operatively connect the running-in string to the traveling block and means are provided for maintaining a predetermined stress in the running-in string. The improvement comprises means attached to the rig and operatively connected to the line extending from the crown block to the support for maintaining a substantially constant pull on the line to remove slack from the line as the predetermined stress maintaining means compensates for movement of the barge.

United States Patent 11 1 Kammerer July 15, 1975 SLACK REMOVAL APPARATUS Primary Examiner-Frank L. Abbott Assistant ExaminerRichard E. Favreau [76] Inventor: Archer W. Kammerer, 800 N. I

Raymond Fullerton Calm 92645 Att0rne Agent, or FlrmW1ll1am F. McDonald [22] Filed: June 8, I972 [57] ABSTRACT 2 Appi N 251 090 An improvement in apparatus for maintaining a predetermined stress 1n a running-in string disposed in a well bore underlying a body of water and which is sup U-S. 166/.5; ported y a g including a derrick and a floor or deck [5 I] ll. Cl. E218 3/06 mounted on a barge or the like floating in the bady of [58] Flfild of Search 175/5, 27. 166/.5; water The g has a block and tackle including a 254/172 crown block and a traveling block with line therebetween. At least one line extends from the crown block [56] References to a support at a lower portion of the rig. Means oper- UNITED S A S PATENTS atively connect the running-in string to the traveling 3.150.860 9/1964 Nelson 254/172 lo k an means are provided for maintaining a pre- 3.l5|.686 I0/l964 Kammcrer 175/5 determined stress in the running-in string. The im- ,206 M11964 Kammerer 175/27 X provement comprises means attached to the rig and 3,3 operatively connected to the line extending from the K Lumerenm" crown block to the support for maintaining a substana CS 1718.316 2/1973 Larralde et al. 175/5 constant the remm'e slack from the line as the predetermined stress maintaining means compensates for movement of the barge.

9 Claims, 4 Drawing Figures SHEET W'XTWTCHUL 15 1975 1 SLACK REMOVAL APPARATUS BACKGROUND OF THE INVENTION The present invention relates to apparatus particularly useful in the drilling, completion, and production of wells. It is particularly applicable to apparatus for supporting running-in strings, such as tubular strings of drill pipe, casings, and tubing, in well bores.

Apparatus for automatically and hydraulically maintaining a substantially constant tension in a running-in string disposed in a well bore, safety weight controls therefore, and hydraulic weight control and compensating apparatus for maintaining the weight imposed by a drilling string on a drill bit constant while a bore hole is being drilled, all of which may be referred to in general as apparatus for maintaining a predetermined stress in a running-in string disposed in a well bore are described in the following U.S. Patents, the subject matter of which to the extent applicable, are incorporated by reference herein: U.S. Pat. Nos. 2,945,676; 2,945,677; 3,151,686; 3,158,206; and 3,158,208. Archer W. Kammerer was the inventor on all the patents, except for U.S. Pat. Nos. 2,945,676 and 2,945,677 of which Archer W. Kammerer, Jr. was the inventor. These apparatuses are effective in maintaining a predetermined stress in a running-in string, particularly such a string which is disposed in a well bore underlying a body of water and which is supported by a rig mounted on a barge or the like floating in a body of water. However, when a block and tackle, including a crown block and a traveling block with lines therebetween, that has at least one line extending from the crown block to a support at the lower portion of the rig is used, a further problem can develop. The lines used in the block and tackle are normally a heavy wire rope. As the means for maintaining the predetermined stress in the running-in string adjusts or compensates for the rise and fall of the barge and rig due to wave action, tidal action, and the like, the line extending from the crown block to the support will flex, alternately becoming slack and increasing in tension. This flexure of the line can cause wear of the line and undesirably shorten the life thereof.

SUMMARY OF THE INVENTION It is an object of the present invention to provide means for maintaining a substantially constant pull on the line of such a block and tackle arrangement to remove slack from the line as a predetermined stress maintaining means compensates for movement of the barge.

It is an advantage of the instant invention that the means attached to the rig and operatively connected to the line extending from the crown block to the support may be fluid pressure operated in the same manner that the predetermined stress maintaining means are operated. It is an advantage of the instant invention that the undesirable flexure is significantly reduced, and therefore the life of the line considerably lengthened.

The present invention provides means for removing slack from the line extending from the crown block to the support. The invention relates to apparatus for maintaining a predetermined stress in a running-in string disposed in a well bore underlying a body of water and which is supported by a rig including a derrick and a deck mounted on a barge or the like, floating in the body of water. The apparatus has a block and tackle, including a crown block and a traveling block with lines therebetween. At least one line extends from the crown block to a support at a lower portion of the rig. Means operatively connect the running-in string to the traveling block. Means are provided for maintaining a predetermined stress in the running-in string. The improvement comprises means attached to the rig and operatively connected to the line extending from the crown block to the support for maintaining a substantially constant pull on the line. This removes slack from the line as the predetermined stress maintaining means compensates for movement of the barge.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front elevational view, partly in section and with parts removed for purposes of clarity, diagrammatically illustrating one application of this invention.

FIG. 2 is a front elevational view, partly in section and with parts removed for purposes of clarity, diagramatically illustrating one application of this invention.

FIG. 3 is a diagramatic view, partly in section and with parts removed for purposes of clarity, of the con stant pull maintaining means and expansion chamber utilized in the embodiment shown in FIG. 2.

FIG. 4 is a front elevational view, partly in section and with parts removed for purposes of clarity, diagramatically illustrating another embodiment of the present invention.

Throughout the drawings, the same reference numerals have been applied to various corresponding parts.

DETAILED DESCRIPTION FIG. 1 illustrates a typical embodiment of the instant invention. The predetermined stress maintaining means 10 of a type, for example, similar to that shown in U.S. Pat. No. 3,158,206 to Archer W. Kammerer, incorporated by reference herein and to which reference is made for the details thereof, is shown operatively associated with a rig indicated at 12 used for drilling a well bore 14 such as a well bore underlying a body of water 16, the mouth of well bore 14 being at the bottom 8 of the body of water 16. The rig 12 includes a derrick 20 and a deck or floor 22 mounted on a barge 24 floating in water 16.

Contained in derrick 20 is a block and tackle indicated generally at 26 having a crown block 28 and a traveling block 30 with lines 32 therebetween, which can be wire rope, fiber lines, cables, or the like, passing over the sheaves (not shown) of crown block 28 and traveling block 30. Hook 34 of traveling block 30 is connected to a swivel 36 secured to the upper kelley portion 38 of drill pipe 40 extending through body of water 16 into bore hole 14, the drill pipe 40 having a suitable drill bit 42 on its lower end for drilling the hole. Suitable drilling fluid is pumped through a mud line 44 into a swivel 36 for downward passage into a drill pipe 40 and for discharge from the drill bit 42, the drilling fluid carrying the cuttings upwardly of the hole 14 and around the drill pipe 40 to the bottom or floor 18 of the body of water 16 for suitable disposal. The string of drill pipe 40 and the bit 42 are rotated in the usual manner by a rotary table 46 through which the kelley 38 is slidably splined. At least one line 48 passes over and extends from crown block 28 to a support at a lower portion of rig 12, the support here being shown as a drawworks 50 mounted on deck 22.

The means for removing slack from line 48 are indicated generally at 52. Means 52 include a cylinder 54 attached to deck 22 of rig 12, as by brackets 56. Cylinder 54 may be provided with an upper cylinder head 58 and a lower cylinder head 60. A piston 62 is secured to a piston rod 64 extending upwardly through the upper cylinder head 58. Rod 64 has a suitable eye 66 at its upper end, to which is secured a wire rope or chain 68. Chain 68 extends upwardly and around a spool or sprocket wheel 70 attached to rig 20 and is slidably connected to line 48 by reel 72.

Leakage around piston 62 is prevented by a suitable packing or seal ring 72 mounted in a groove provided in piston 62. A suitable vent 74 is provided in the vicinity of lower cylinder head 60.

Cylinder 54 is completely filled with a suitable fluid, for example a liquid such as oil, between piston 62 and the upper cylinder head 58. The fluid is derived from a suitable reservoir 76 which constitutes a source of fluid, and in turn is connected to a pump 78. The fluid discharges from pump 78 through an inlet line 80 having a pressure indicating gage 82 attached thereto and opening into the upper portion of cylinder 54. An outlet line 84 is also connected to the upper portion of cylinder 54, this outlet line returning the fluid to reservoir 76. The outlet line includes a check valve 86 as a flow restricting instrumentality for creating a back pressure in the fluid in cylinder 54 above piston 62 and inlet line 80, so that fluid under a desired pressure is contained in cylinder 54 above piston 62 to maintain a substantially constant pull on line 48. It will be appreciated that inlet line 80 constitutes a means for constantly feeding fluid under pressure to cylinder 54 and outlet line 84 constitutes a means for constantly conducting the fluid from cylinder 54. Pump 78 constantly forces fluid under pressure into cylinder 54 above piston 62, the fluid constantly passing out by means of outlet line 54 back to reservoir 76 to continuously repeat the cycle.

The operation of the instant invention may be briefly summarized. As the deck 22 rises, and crown block 28 starts to rise due to the movement of water 16, cylinder 54 also rises. Stress maintaining means compensates for the movement of barge 24 and causes a movement of the block and tackle 26 lowering crown block 28 and maintaining the position of block and tackle 26 and drill string 40 substantially constant. This results in some slack being put in line 48. The fluid pressure generated by pump 78 will move piston 62 in cylinder 54 to maintain a substantially constant pull and remove the slack therefrom. As deck 22 together with derrick fall, the reverse occurs.

In the embodiment of the instant invention shown in FIG. 2, an expansion chamber indicated generally at 88 is mounted on deck 22 and is in fluid communication by conduit 90 with cylinder 54 of slack removing means 52 to allow fluid under pressure to transfer between cylinder 54 and chamber 88. The exact arrangement and operation of expansion chamber 88 will not be explained in detail here. A detailed explanation may be found in U.S. Pat. No. 3,151,206 which is incorporated by reference herein and to which reference is made for this purpose. As a simplified explanation of the arrangement of expansion chamber 88 it may be noted that expansion chamber 88 includes an expansion cylinder 92 in fluid communication with cylinder 54 by means of conduit which can be an appropriate interconnecting pipe or line.

Slidable vertically in expansion cylinder 92 is an expansion piston 94 having a piston rod 96 secured thereto which extends downwardly through a lower cylinder head 98. Piston rod 96 is firmly secured to a partially or fully submerged hollow float structure 100 which tends to move upwardly in a body of water 16 but which is anchored against such upward movement by a plurality of anchor cables 102 secured thereto and appropriately secured to the bottom 18 of the body of water 16, as for example, by being anchored to a concrete anchor block 104 buried in bottom 18. Hollow float structure 100 is buoyed by the water 16 and tends to move upwardly, but such upward movement is restricted by the anchor cables 102. Where a well is being drilled in very deep water, which may be several thousand feet deep, and in fact, 15,000 to 20,000 feet deep is not unusual, the weight of the cables 102 will tend to counteract the buoyancy of the hollow float structure 100, buoying it downwardly as well as the piston 96 secured thereto. The weight of the cables can be offset by attaching suitable floats 106 thereto, which may be hollow, which will tend to buoy cables 102 and maintain them in tension throughout their length.

Hollow float structure 100 will remain in a fixed position, which is also true of rod 96 and expansion piston 94 secured thereto, barge 24 being guided in its vertical movement along hollow float structure 100 by verticle guide members 108 secured to the barge 24 and extending downwardly therefrom. Guide members 108 are freely moveable along hollow float structure 106, as by providing suitable rollers 110 on float structure 100 or on guide 108, that rollably engage the other member. Expansion cylinder 92 above expansion piston 94 is filled with fluid which is prevented from leaking past expansion piston 94 by a suitable piston ring 1 12.

Again, reference is made to U.S. Pat. No. 3,151,206, incorporated by reference herein, for a detailed explanation of the expansion chamber and its various parts.

It should be noted that in this embodiment slack removing means 52 is attached to derrick 20 of rig 12. A suitable packing 114 is positioned around piston rod 64 and upper cylinder head 58 to prevent leakage of fluid from the cylinder 54. It should also be noted that in this embodiment the flow restricting instrumentality in outlet line 84 is a restriction 106 having an orifice therein.

in the embodiment of the present invention shown in FIG. 4, it will be seen that line 48 extends from drawworks 50 and over and around the crown block 28 and traveling block 30 as lines 32 and continues after passing once again around crown block 28 to a deadhead 118 at a lower portion of rig 12 for example, deck 22, the last mentioned portion of the line being designated as 120. In this embodiment a second slack removing means 52 is attached to rig l2 and operatively connected to line 120 between crown block 28 and deadhead 118 for maintaining a substantially constant pull on line 112 which removes slack from line 112 as the predetermined stress maintaining means 10 compensates for movement of barge 24. in the embodiment shown both slack removing means 52 are shown attached to derrick 20 of rig 12. However, it can be readily appreciated that either or both of them could with equal facility be attached to deck 22 of the rig, in the manner shown in FIG. 1.

While there have been shown and described hereinabove possible embodiments of this invention, it is to be understood that the invention is not limited thereto and that various changes, alterations, and modifications can be made thereto without departing from the spirit and scope thereof as defined in the claims.

What is claimed is:

L In apparatus for maintaining a predetermined stress in a running-in string disposed in a well bore underlying a body of water and which is supported by a rig including a derrick and a deck mounted on a barge, or the like, floating in the body of water and having a block and tackle, including a crown block and a traveling block with lines therebetween, at least one line extending from the crown block to a support at a lower portion of the rig, means operatively connecting the running-in string to the traveling block, and means for maintaining a predetermined stress in the running-in string, the improvement which comprises means attached to the rig and operatively connected to the line extending from the crown block to the support and separate from the crown block and support for maintaining a substantially constant pull on the line to remove slack from the line as the predetermined stress maintaining means compensates for movement of the barge which comprises:

a. a cylinder;

b. a piston slidable relatively in the cylinder and constituting with the cylinder a piston-cylinder assemc. first means attaching the piston-cylinder assembly to the rig,

d. second means slidably connecting the pistoncylinder assembly to the line, one of the first and second means being attached to the piston and the other to the cylinder so that the piston is moveable longitudinally along the cylinder; and

e. means for maintaining fluid under substantially constant pressure in the cylinder and on the piston as the piston and cylinder move longitudinally relative to each other, and whereby a substantially constant pull is maintained on the line to remove slack from the line as the predetermined stress maintaining means compensates for movement of the barge,

and including the following additional elements:

f. means for constantly feeding fluid under pressure to the cylinder;

g. means for constantly conducting the fluid from the cylinder; and

h. a flow restricting instrumentality in the conducting means for creating a back pressure in the fluid in the cylinder.

2. The apparatus of claim 1 wherein the flowrestricting instrumentality is a restriction in the conduit having an orifice.

3. The apparatus of claim 1 wherein the flow restricting instrumentality is a check valve.

4. The apparatus of claim 1 wherein the means for maintaining fluid under substantially constant pressure in the cylinder has fluid therein at substantially the same pressure as the cylinder, and including an expansion chamber in fluid communication with the cylinder to allow fluid under pressure to transfer between the cylinder and chamber.

5. The apparatus of claim 1 wherein the means for constantly feeding fluid under pressure to the cylinder comprises:

a. a source of fluid; and

b, a pump connected to the source and the cylinder for constantly forcing fluid under pressure into the cylinder.

ti. The apparatus of claim 5 wherein the means for constantly conducting the fluid from the cylinder is connected to the source of fluid whereby the fluid from the cylinder is conducted back to the source.

7. The apparatus of claim 1 wherein the support at a lower portion of the rig is a drawworks.

8. The apparatus of claim 7 wherein the line extends from the drawworks and over the crown block and traveling block and to a deadhead at a lower portion of the rig.

5h The apparatus of claim 8 including means attached to the rig and operatively connected to the line between the crown block and deadhead for maintaining a substantially constant pull on the line to remove slack from the line as the predetermined stress maintaining means compensates for movement of the barge.

i l i 

1. In apparatus for maintaining a predetermined stress in a running-in string disposed in a well bore underlying a body of water and which is supported by a rig including a derrick and a deck mounted on a barge, or the like, floating in the body of water and having a block and tackle, including a crown block and a traveling block with lines therebetween, at least one line extending from the crown block to a support at a lower Portion of the rig, means operatively connecting the running-in string to the traveling block, and means for maintaining a predetermined stress in the running-in string, the improvement which comprises means attached to the rig and operatively connected to the line extending from the crown block to the support and separate from the crown block and support for maintaining a substantially constant pull on the line to remove slack from the line as the predetermined stress maintaining means compensates for movement of the barge which comprises: a. a cylinder; b. a piston slidable relatively in the cylinder and constituting with the cylinder a piston-cylinder assembly; c. first means attaching the piston-cylinder assembly to the rig; d. second means slidably connecting the piston-cylinder assembly to the line, one of the first and second means being attached to the piston and the other to the cylinder so that the piston is moveable longitudinally along the cylinder; and e. means for maintaining fluid under substantially constant pressure in the cylinder and on the piston as the piston and cylinder move longitudinally relative to each other, and whereby a substantially constant pull is maintained on the line to remove slack from the line as the predetermined stress maintaining means compensates for movement of the barge, and including the following additional elements: f. means for constantly feeding fluid under pressure to the cylinder; g. means for constantly conducting the fluid from the cylinder; and h. a flow restricting instrumentality in the conducting means for creating a back pressure in the fluid in the cylinder.
 2. The apparatus of claim 1 wherein the flow-restricting instrumentality is a restriction in the conduit having an orifice.
 3. The apparatus of claim 1 wherein the flow restricting instrumentality is a check valve.
 4. The apparatus of claim 1 wherein the means for maintaining fluid under substantially constant pressure in the cylinder has fluid therein at substantially the same pressure as the cylinder, and including an expansion chamber in fluid communication with the cylinder to allow fluid under pressure to transfer between the cylinder and chamber.
 5. The apparatus of claim 1 wherein the means for constantly feeding fluid under pressure to the cylinder comprises: a. a source of fluid; and b. a pump connected to the source and the cylinder for constantly forcing fluid under pressure into the cylinder.
 6. The apparatus of claim 5 wherein the means for constantly conducting the fluid from the cylinder is connected to the source of fluid whereby the fluid from the cylinder is conducted back to the source.
 7. The apparatus of claim 1 wherein the support at a lower portion of the rig is a drawworks.
 8. The apparatus of claim 7 wherein the line extends from the drawworks and over the crown block and traveling block and to a deadhead at a lower portion of the rig.
 9. The apparatus of claim 8 including means attached to the rig and operatively connected to the line between the crown block and deadhead for maintaining a substantially constant pull on the line to remove slack from the line as the predetermined stress maintaining means compensates for movement of the barge. 